1. I clearly remember to put/putting the book on the shelf. I wonder why it's not there.
2. I hope you remembered to do/doing the groceries on your way home. We've run out of milk and bread.
3. Here! Try to unlock/unlocking the box with this key again.
4. You should definitely try to do/doing yoga. You'll be full of energy, believe me!
5. It seems my cat regrets to break/breaking my favourite vase.
6. I regret to tell/telling you that you've failed our entrance exams.
7. My friend has become concerned about environmental issues. She stopped to drink/drinking coffee in plastic cups.
8. Whenever I'm in that part of the city, I stop to have/having a snack in my favourite cafe.